Regulation of Collagenase and Bone Resorption. This grants consists of biochemical and morphological studies designed to elucidate the mechanism of bone resorption. Based on the accumulated evidence that the enzyme collagenase is involved in the degradation of tissue collagen during bone resorption, we plan to study the regulation and localization of bone collagenase during the process of bone resorption with special attention to alveolar bone resorption in periodontal disease. New knowledge of tissue collagenase of bone and periodontal tissues in health and disease will be of basic value in developing a method to control and prevent bone resorption, thereby preventing alveolar bone loss in periodontal disease. The objectives are: 1. Isolation and characterization of procollagenase and collagenase inhibitor, and studies on their modes of action and interaction in isolation and during bone resorption. 2. Immunochemical localization of collagenase at light and electron microscopic levels in mouse calvaria cultured under various conditions and in isolated mouse bone cells using immunofluorescence and immunoperoxidase antibody techniques. 3. Mouse bone collagenase antibofdy and bone resorption: The studies on the effect of the antibody on bone resorption in tissue culture. 4. A search for a new avenue to study bone resorption: On the possivle role of collagenolysis-products; bone collagen peptides in bone resorption. Isolation and characterization of bone collagen peptides from bone cultures and from digests of bone matrix collagen by mouse bone collagenase, and tests of their possible ability to elicit chemotactic responses in isolated mouse bone cells, monocytes and macrophages.